2197铝锂合金的耐热性能

Heat resistant properties of 2197 Al-Li alloy

研究了2197铝锂合金的高温拉伸性能以及长时间热暴露后的室温力学性能,同时对合金热暴露前后的显微组织进行透射电镜观察。结果表明:2197合金的高温拉伸强度随拉伸温度的升高而逐渐降低,在200℃下的高温拉伸性能优于传统高温用铝合金;在低于150℃的温度下热暴露100 h后,2197合金的强度略有上升,这与T1相具有较强的抗粗化能力及θ′相的二次析出有关;但在200℃和250℃热暴露条件下,合金的力学性能快速下降,这与在此温度下θ′相的溶解和T1相的快速粗化有关。

The tensile properties at elevated temperatures and the room-temperature properties after long time thermal exposure of 2197 alloy were studied. Microstructures of 2197 alloy after long time thermal exposure at different temperatures were observed by TEM. The results show that the tensile strength at elevated temperatures decreases with increasing test temperature, and the tensile properties at 200 ℃ are higher than those of traditional aluminum alloy used at elevated temperature. After exposure at temperatures below 150 ℃ for 100 h, the mechanical properties of 2197 alloy increase slightly. This is related to the high coarsening resistance of T1 phase and secondary precipitation of θ＇ phase at these temperatures. However, after exposure at 200 ℃ and 250 ℃ for 100 h, the mechanical properties of 2197 alloy decrease rapidly due to the dissolution of θ＇ phase and rapid coarsening of T 1 phase at these temperatures.